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Re: [TowerTalk] ID of A3s boom

To: george <>
Subject: Re: [TowerTalk] ID of A3s boom
From: Tom Carrubba KA2D <>
Date: Thu, 15 Mar 2007 09:51:27 -0400
List-post: <>
Hello George

I did not read your entire post the first time around. This
is a common problem..

We solved this problem by pinning the elements to boom.
We used #8 stainless screws though the clamps into the boom.
You also need to index the boom if you plan on disassembly
in future.

Our club uses the A3 for FD, local lighthouse and Skywarn
Recognition day. The A3 is now over 10 years old...

Hopes this helps
Tom KA2D

----- Original Message ----- 
From: "Bill Coleman" <>
To: "george" <>
Cc: <>
Sent: Wednesday, March 14, 2007 11:08 PM
Subject: Re: [TowerTalk] ID of A3s boom

On Mar 11, 2007, at 11:33 PM, george wrote:

> Anyone know the dimensions of the inside of the boom on a
> A3S?
> I am looking to install wooden dowels into the ends to
prevent the
> elements
> from turning.

I've had my A3S up at three different locations for about 13
total, and never had any problem with the elements turning
on the
boom. Do you have the elements properly assembled on the
boom with
the U-bolts coming down from the top and the saddles
underneath? With
the element hanging below the boom, the antenna should
naturally seek
to hold the elements level. (I have seen many a Cushcraft
antenna at
Field Day improperly assembled with the elements upside

According to the manual, the boom is 1 1/2" OD. The manual
say, but the boom is 0.058" wall, which means the next size
lower, or
1 3/8" tubing will slip inside it. So, a 1 3/8" dowel should

One warning about forcing a dowel into the end of tubing
like this -- 
you will be trapping moisture inside the boom, which will
hasten the
corrosion of the interior of the boom, especially in the
area where
the dowel contacts the tube.

Bill Coleman, AA4LR, PP-ASEL        Mail:
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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